/*
 * Copyright 2016-2017 ZTE Corporation.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.openo.sdnhub.sptndriver.utils;

import org.apache.commons.net.util.SubnetUtils;

/**
 * The Utility class to convert IPV4.
 */
public class Ipv4Util {

    private Ipv4Util(){}

    /**
     * Get the IP part from the full IP "a.b.c.d/mask".
     *
     * @param ip Full IP address like "a.b.c.d/mask"
     * @return IP address like "a.b.c.d"
     */
    public static String getDotIp(String ip) {
        if (ip != null) {
            String[] parts = ip.split("/");
            if (parts.length > 0) {
                return parts[0];
            }
        }
        return ip;
    }

    /**
     * Get IP mask from full IP "a.b.c.d/mask", and return in forms of "255.255.255.0".
     *
     * @param ip "a.b.c.d/mask"
     * @return IP mask like "255.255.255.0", return "255.255.255.255" if input IP like "a.b.c.d"
     */
    public static String getDotMask(String ip) {
        if (ip == null) {
            return null;
        }
        String mask;

        String[] parts = ip.split("/");
        if (parts.length >= 2) {
            mask = parts[1];
        } else {
            return "255.255.255.255";
        }

        if (mask.contains(".")) {
            return mask;
        }
        return ipInt2DotStr(Integer.parseInt(mask));
    }

    /**
     * Transform integer mask to string dot mask.
     *
     * @param intMask Integer value of mask, like 24
     * @return Mask in form of "255.255.255.0"
     */
    private static String ipInt2DotStr(int intMask) {
        String cidr = "255.255.255.255/" + intMask;
        SubnetUtils subnet = new SubnetUtils(cidr);
        return subnet.getInfo().getNetmask();
    }
}
